Launder assembly and launder section

ABSTRACT

One aspect of the invention concerns a launder assembly ( 10 ) for conveying molten material from a metallurgical furnace, The assembly is made up of launder sections ( 12 ) arranged end to end with connections between adjacent ends of the launder sections. Each launder section includes a base ( 14 ) and spaced apart side walls ( 16, 18 ). At each connection between the adjacent ends of two launder sections, the bases of the launder sections are formed with recesses ( 28 ) which, in combination, form a cavity ( 32 ). A connector ( 34 ) is located in the cavity and in that the bases of the launder sections are connected to one another through the connector. In the preferred arrangement, the bases of the launder sections are connected to the connector by fasteners, typically bolts ( 38 ) which engage the bases and in threaded holes ( 42 ) in the connector.

BACKGROUND TO THE INVENTION

THIS invention relates to a launder assembly and to an individual launder section of the assembly. In particular the invention is concerned with a launder assembly and section for channeling molten material such as slag, metal or matte from a metallurgical furnace.

High temperature liquid material generated in a metallurgical furnace is generally fed from the furnace with the use of trough-shaped launders. Due to the extreme temperatures of the liquid material conveyed by launders, water cooling ducts are often provided therein for cooling purposes.

Traditionally the launder is constructed by placing launder sections, each having flanges on their sidewalls, end to end in series and connecting the sections together by means of bolts passing through the adjacent flanges at the sides of the launder sections.

In use the base of the assembled launder is typically subjected to more heat that the upper side sections thereof. Also, because the launder sections are connected only by the side wall flanges, the bases of the launder sections may be relatively insecurely connected to one another. As a result of these features, gaps may in use open up between the bases of the launder sections while the sidewalls will remain tightly connected. It is then possible for molten liquid to leak from the launder through any such gaps which may form in the base. In extreme instances the leaking, high temperature liquid could come into contact with cooling water in the cooling ducts, potentially leading to an explosion and consequential damage to the launder.

It is an object of the invention to provide a launder assembly and launder section having a reduced potential for gaps to form in the base.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention there is provided a launder assembly for conveying molten material, the assembly comprising a plurality of launder sections arranged end to end with connections between adjacent ends of the launder sections, each launder section including a base and spaced apart side walls, characterised in that, at each connection between the adjacent ends of two launder sections, the bases of the launder sections are formed with recesses which, in combination, form a cavity, in that a connector is located in the cavity and in that the bases of the launder sections are connected to one another through the connector.

In the preferred arrangement, the bases of the launder sections are connected to the connector. This may be achieved by means of fasteners, typically bolts which pass through passages in the bases of the launder sections and into threaded holes in the connector.

Advantageously the bases of the launder sections have undersides and are formed with further recesses open to the undersides of the bases, and the bolts extend from the further recesses and through passages in end regions of the bases into the threaded holes in the connector. In this way, the bolts are recessed with respect to the undersides of the bases.

The connection system summarised above provides a good connection between the bases of the launder sections and hence reduces the chances of any gap opening up at this location. Further security against leakage is present where the connector has a length, measured transverse to the launder assembly, i.e. transverse to the flow of molten liquid in the launder assembly, which is at least equal to the width of the trough defined by the base and side walls, at a bottom of the trough. With this feature, the connector provides a physical barrier to leakage which may take place through any gap which does open up.

Preferably the launder sections are made of metal and the connector is a billet made of metal which is harder than the metal of which the launder sections are made. In one specific embodiment, the launder sections are made of copper and the billet is made of steel. The bases of the launder sections may be formed with spaced apart rows of further recesses, such rows defining between them a reinforcing rib for the launder section. This is particularly advantageous where the launder sections are made of a relatively soft material such as copper.

According to another aspect of the invention there is provide a launder section for connection end to end with another, similar launder section in order to form a launder assembly suitable for conveying molten material, the launder section including a base and spaced apart side walls, characterised in that the base of the launder section, at an end thereof which is to be connected to an end of the other launder section, is formed with a first recess arranged to form, in combination with a corresponding first recess in the base of the other launder section, a cavity to receive a connector, and in that the launder section has at least one passage therein, communicating with the first recess, to receive a fastener for connecting the base of the launder section to the connector.

In the preferred launder section, the base has an underside and is formed with further, second recesses open to the underside, and each passage extends within an end region of the base from a second recess near to the end of the launder section to the first recess. There may be two passages each of which extends within an end region of the base from a second recess to the first recess. As indicated above, the second recesses can be arranged in spaced apart rows which define between them a reinforcing rib for the launder section.

For the reason mentioned above, it is preferred that the first recess have a length, measured transverse to molten material flow in the trough defined by the base and side walls of the launder section, which is at least equal to the width of the trough.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings, in which:

FIG. 1 diagrammatically illustrates, in a perspective view from below, a portion of a launder assembly in accordance with the present invention; and

FIG. 2 shows a diagrammatic cross-sectional view illustrating a portion of the base of the launder assembly.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENT

FIG. 1 shows a perspective view on the underside of a launder assembly 10 according to this invention. The illustrated portion of the launder assembly 10 includes identical first and second launder sections 12 each having a base 14 and spaced apart side walls 16 and 18.

The launder sections 12 are connected end to end to one another and, if necessary, to other similar launder sections in order to form the complete launder assembly. Persons skilled in the art will understand that the base and side walls of each of the launder sections form an internal trough. These troughs, in combination in the launder assembly, define a continuous internal channel 20 in which a molten liquid material such as slag, metal or matte (for convenience hereinafter referred to merely as “slag”) can be conveyed from a metallurgical furnace.

Flanges 22 are secured to the side walls 16 and 18 of each launder section, towards each end thereof, by means of bolts 24. The flanges 22 are connected to one another by bolts 26 which accordingly serve to connect the side walls of the sections to one another.

At the end of each launder section, the base 14 is formed with a first recess 28. With the launder sections arranged end to end the recesses 28 at the adjacent ends combine to form a cavity 32. A connector, in this case in the form of an elongate, rectangular section connector 34, is located in the cavity.

In addition to the recesses 28 at each end, the base 14 of each launder section 12 is formed with a series of further, second recesses 36 arranged in two longitudinally extending rows. As shown in FIG. 2, the recesses 36 have a depth, measured from the underside 38 of the launder section, which is substantially less than the vertical thickness of the base 14. FIG. 2 also shows that the billet 34 has a vertical thickness substantially less than the thickness of the base 14 and somewhat less than the depth of the recesses 36. The billet typically has a length, transverse to the length of the launder assembly, i.e. transverse to the direction of molten material flow in the launder assembly, which is equal to or greater than the width of the channel 20 at its bottom, so that the billet extends fully across the launder assembly for the full width of the bottom of the trough. It will be understood that the recesses 28, and accordingly the cavity 32, must have a corresponding length, measured transversely, to accommodate the billet 34.

The bases of the illustrated launder sections, are connected to one another, by means of the billet 34 and bolts 38. As illustrated, each bolt 38 extends from an end recess 38.1 through a passage 40 in an end region of the base of the launder section with the threaded shank of the bolt engaged in a tapped, i.e. threaded, hole 42 in the billet. With this arrangement, the bases of both illustrated launder sections are connected to the intermediate billet and are accordingly connected to one another through the billet. In the launder assembly, the heads 44 of the bolts are located in the end recesses 38.1 as illustrated.

As persons familiar with launder assemblies used with furnaces will know, the launder sections of the launder assembly will often be made of copper due to its favourable thermal characteristics which in use allow for good transference of the cooling effects of cooling water circulated inside ducts (not shown) extending within the walls of the launder sections. The copper is however relatively soft. The billet 34 is typically made of steel or other metal which is harder than the copper of which the launder sections are made. The illustrated base connection system avoids any requirement for tapped threads in the soft copper and allows the billet 34 to distribute the connecting force over a substantial area of the copper, thereby reducing the chances of possible damage to the copper.

In combination with the side wall connections provided by the flanges 22, the billet 34 establishes a robust connection between the adjacent launder sections. The use of the billet reduces the likelihood of a gap opening up between the bases of the launder sections. In the unlikely event of a gap opening up in this region, the billet will also reduce the chances of leakage of molten slag.

As indicated above, the recesses 38 in the bases of the launder sections are arranged in longitudinally extending rows. The arrangement is such that a continuous, longitudinally extending rib 46 is formed between the rows of recesses. In each launder section, the rib 46 advantageously provides longitudinal reinforcement to the launder section.

Although it has specifically been mentioned that the launder sections may be made of copper, it will be recognised that other suitable materials, such as Meehanite™, cast iron and cast steel could also be used. In these cases as well, the connection of the bases of the launder sections via a billet, as described above, will also be advantageous.

The term “launder” has been used to refer to a trough-shaped component suitable for conveying molten slag and other materials in furnace operations, and specific mention has been made of a launder assembly made up of straight launder sections. It must be recognised that the principles of the invention are applicable to trough-shaped channels other than straight launders, for example runners and spouts as are also used in such operations, and accordingly that the term “launder” should be interpreted in a broad sense to include such components. 

1. A launder assembly for conveying molten material, the assembly comprising a plurality of launder sections arranged end to end with connections between adjacent ends of the launder sections, each launder section including a base and spaced apart side walls, characterised in that, at each connection between the adjacent ends of two launder sections, the bases of the launder sections are formed with recesses which, in combination, form a cavity, in that a connector is located in the cavity and in that the bases of the launder sections are connected to one another through the connector.
 2. A launder assembly according to claim 1 wherein the bases of the launder sections are connected to the connector.
 3. A launder assembly according to claim 2 comprising fasteners which connect the bases of the launder sections to the connector.
 4. A launder assembly according to claim 3 wherein the fasteners are bolts passing through passages in the bases of the launder sections and into threaded holes in the connector.
 5. A launder assembly according to claim 4 wherein the bases of the launder sections have undersides and are formed with further recesses open to the undersides of the bases, and the bolts extend from the further recesses and through passages in end regions of the bases into the threaded holes in the connector.
 6. A launder assembly according to claim 1 wherein the assembly defines a trough to convey a flow of the molten material and the connector has a length, measured transverse to such flow, at least equal to the width of the trough at a bottom of the trough.
 7. A launder assembly according to claim 1 wherein the launder sections are made of metal and the connector is a billet made of metal which is harder than the metal of which the launder sections are made.
 8. A launder assembly according to claim 7 wherein the launder sections are made of copper and the billet is made of steel.
 9. A launder assembly according to claim 1 wherein the bases of the launder sections are formed with spaced apart rows of further recesses, such rows defining between them a reinforcing rib for the launder section.
 10. A launder section for connection end to end with another, similar launder section in order to form a launder assembly suitable for conveying molten material, the launder section including a base and spaced apart side walls, characterised in that the base of the launder section, at an end thereof which is to be connected to an end of the other launder section, is formed with a first recess arranged to form, in combination with a corresponding first recess in the base of the other launder section, a cavity to receive a connector, and in that the launder section has at least one passage therein, communicating with the first recess, to receive a fastener for connecting the base of the launder section to the connector.
 11. A launder section according to claim 10 wherein the base has an underside and is formed with further, second recesses open to the underside, and each passage extends within an end region of the base from a second recess near to the end of the launder section to the first recess.
 12. A launder section according to claim 11 wherein there are two passages each of which extends within an end region of the base from a second recess to the first recess.
 13. A launder section according to claim 11 wherein the second recesses are arranged in spaced apart rows which define between them a reinforcing rib for the launder section.
 14. A launder section according to claim 10 wherein the base and side walls define a trough to convey a flow of molten material and the first recess has a length, measured transverse to such flow, at least equal to the width of the trough at a bottom of the trough. 